Revolving grizzly



Jan. 22, 1929. 1,699,718

T. ROBINS BEVOLVING GRIzzLY Patented dan.. 22, 1929.

STATES j 1,699,718Y PATENT OFFICE.

THOMAS ROBINS, F NEW YORK, N. Y., ASSIGNOR TOBIOBINS CONVEYING BELT COM- PANY, OF PASSAIC, NEW JERSEY, A CORPORATION OF NEW JERSEY.

REVOLVING GRIZZLY.

Application filed April 6,

This invention relates to revolving grizzlies wherein a succession of separating rolls are supported in close parallel relation; having reference to grizzlies designed for screening hard irregular material, such, for eX- ample, as stone, ore and the like. The said rolls, which are usually supported in an inclined plane, are provided with circumferential grooves arranged to present separat- 1o ing openings between adjacent rolls, the

shafts of the rolls being mechanically connected in such manner as to effect the rotation of all the rolls in the same direction but with progressively increasing Speeds from the uppermost to the lowermost roll. The direction of rotation of the rolls is such as to advance the material downthe inclined plane of the grizzly, which stream impinges first upon the uppermost set of rolls that travel at 2o the slowestspeed, and is then carried down the plane at an increasing speed from roll to roll, the last roll rotating at the highest speed.

In its travel from roll to roll material smaller than the size of the openings between adjacent rolls falls through the openings, while the oversize materialtravels over the rolls to and is rejected at the foot of the screen. Joggling or agitating of the mass of travelling material and the removal of the oversize and undersize units therefrom are effected by the passage of the material into and over the successive valleys and ridges afforded by the series of rolls, this .action causing the smaller to free themselves from the lare'er sizes and rapidly to screen themselves t irough the mass of coarse material.

rlhe oversize material in its travel down the rotating grizzly rolls, momentarily rests in the valleys between the adjacent rolls, and by reason of the opposite motion of the opposing surfaces of the rolls in frictional contact with such material, the downwardly moving surface tends to drag the material through the openings while the upwardly moving surface tends to drag the material out of the openings, that is to say, the combined action of the frictional forces upon the interposed material seated in the openings tends to rotate Athe material in directions opposite to those of the respective surfaces of the rolls in contact with the material. Since the upward surface speed of the lower roll is greater than the downward surface speed of the adjacent upper roll, the resultant fric- 1927. Serial N0. 181,367.

tional action on the material tends to eject it from the openings.

'Ihe purposeof the speed differential of the rolls is to keep the openings between the adjacent rolls free from clogging pieces. How: ever, in the case of stone, ore and the like the irregularities of the revolving oversize lumps which are lodged between the rigid cylindrical surfaces of the rotating rolls, exert on the rolls a powerful spreading force which is transmitted to the shafts, bearings, gearing and frame of the grizzly. Ithas therefore been necessary heretofore in grizzlies employinfr har'd surface rolls to make the rolls sufficiently strong and rigid to crush the interposed lumps of hard irregular material. This necessitated a relatively large and heavy structure requiring enormous operating power. i

` I have discovered that rubber possesses all the attributes for grizzly rolls employed in the operation of screening, since rubber not only has the requisite strength and wearresisting quality for the screening of hard materials, but it also has suicient inherent elasticity to absorb the crushing reactions set." up by the revolving hard ,irregular lumps which tend to lodge in the openings between adjacentv rolls, thus .preventing the transmission of the destructive stresses to the shafts, or to the bearings, or to the frame of the grizzly. Moreover, such stresses cannot react upon the chains or gears which are 'used to transmit the power to the machine. By virtue of rubbers greater coetlicient of friction, as compared with metal,v the ore or stone being screened is propelled along a rubber roll grizzly more p'ositivelythan it is on the metal roll grizzly. In fact, with the latter type of grizzly it' is necessary to set the machine at a considerable inclination, generally about 20 from the horizontal, whereas with the rubber roll construction the machine efficiently performs its function when in a horizontal position. The provision of rolls 100 of rubber, or equivalent material, enables the construction of a grizzly of considerably less weight and size than heretofore for a given capacity of production, and also materially reduces the operating horse-power require- 105 ments as compared with a metal roll grizzly, thus economizing in the initial cost, cost of maintenance, power consumption, etc..

Therefore, in pursuance of my invention, I construct the rolls in whole or in part of rub- 11 ceiving end portion of the apparatus.

Fig. 3 is a section through the adjacent shafts of a pair of rolls showing anoversize lump of material as lodged in an opening between the rolls.

Fig-4 is a section through a portion of a sectional roll and its shaft.

Referring to the drawings, 5 designates a series of juxtaposed separating rolls having formed therein at spaced intervals throughout their length annular grooves 6, which are so disposed that the grooves of adjacent rolls are oppositely related to each other to present appropriate screening openings. These rolls are carried by parallel shafts 7 whichl are mounted in a suitable frame structure 8 and which shafts are successively connected, as, for example, by sprocket gearing 9 at one side of the structure, so as to be simultaneously and continuously driven in the same direction when one of the shafts is actuated from a suitable -source of power, as usual. The gearing between the succeeding 'shafts is such as to increase their speedprogressively from the receiving to the delivery end of the apparatus, as previously mentioned.

Supported on the frame structure are longitudinal skirt boards 10 for the guidance of the material on the rolls.

According to my invention each of the rolls 5 is composed of a series of counterpart sections of rubber or equivalent material hav- -ing the characteristics described, which sections are arranged side by side and are keyed or otherwise fixed upon the supporting shaft.; although if desired each roll may be an integral body fixed on the shaft.` In the present instance the shaft is formed with a longitudinal keyway 11 and the centrally perforated sections are forced on the shaft, the rubber thus entering the keyway, as indicated at 12, and ensuring a reliable connection.

While my"invention has been especially designed for use in connection with a grizzly for the screening of hard irregular' material, such as stone and ore, yet it is manifest that a grizzly embodying m invention may be utilized with advantage or the screening of friable material, such as coke, since the resilent surfaces of the separating rolls will perform the function of protecting the material as well as the machine from breakage.

It is to be understood that the term rubber as used in the appended claims is in* tended to include any other material havingr characteristics similar to rubber and adapted to the same use, that is, any suitable wearresist-ing material having a resilient cush ioning surface which absorbs the crushing reactions set up by objects which may become lodged in the separating openings between the adjacent rolls of a grizzly, and which surface by its high coeflicient of friction also positively propels the material superposed t.hereon.

I claiml. In a revolving grizzly, a succession of rolls mounted in parallel relation and having co-related circumferential grooves which provide separating openings between adjacent rolls, said rolls each comprising a shaft and a circumferentially-grooved body of rubber thereon affording a solid resilient back ing between the grooves and the shaft, said rubber possessing substantial wear-resisting quality and a high coefficient of friction effective to propel hard material across the periphery of the roll, and having also suficient inherent elasticity to absorb the crushing reactions setnp by irregular objects which may become lodged in the openings between adjacent rolls, and means for simultaneously rotating the said rolls in the same direction.

2. In a revolving erizzy, a succession of rolls mounted in parallel relation and having co-related circumferential grooves which provide separating openings between adjacent rolls, said rolls each comprising a shaft and a circumferentiallygrooved body of rubber thereon affording a solid resilient backing between the grooves and the shaft, said rubber possessing substantial wear-resisting quality and a high coefficient of friction ef4 fective to propel hard material across the periphery of the roll, and having also sufficient inherent elasticity to absorb the crushing reactions set up by hard irregular objects which may become lodged in the openings be tween adjacent rolls, and means for siniultaneously rotating the said rolls in the same direction, and with progressively increasing speeds from the receiving to the discharging,Y end of the grizzly.

3. A revolving grizzly comprising a supporting frame, a pluarlity of spaced-apart parallel shafts, separating rolls mounted on said shafts in close proximity to cach other, cach of said rolls comprising a series of cen- -trallyperforated sections of rubber having resilient walls integral with a resilient shock absorbing backing, and means for rotating the said shafts in the same direction.

4. A revolving grizzly comprising a supporting frame, a plurality of spaced-apart parallel shafts whereof each shaft is provided with a longitudinal keyway, separating rolls mounted on said shafts in close proximity to each other, each of said rollscomposed of a series of centrally perforated sections of rubber forced on the sha-ft and inter'- -4 resilient Walls integral Witha resilient shock locked with the keywa of the shaft, said sections being periphera ly shaped to provide aI series of circumferential grooves having absorbing backing. y i

5. A grizzy rollcomprising a circumferentially grooved body of rubber .possessing substantial Wear-resisting quality and a high coefficient of friction together lwith suiicient inherent elasticity to absorb crushing vreactions.

6. A revolving grizzlyl embodying a series of screening rolls having circumferential' lscreening openings between adjacent rolls, and means for rotating said rolls in the same direction to effect the propulsion .of hard material across the succeeding rolls, said rolls comprising thick rubber bodies having circumferential screening openings formed therein-` and being `of such character that the crushing stresses set up by the counterrevolution of irregular lumps of hard Inaterial lodged between adjacent rolls are absorbed.

. SignedA at New York in the county and State of NewYork this 31st 'day/of March,

l 'THOMAS-ROBINS. l i 

